It is known that part of the raw material used for the production of PET containers, especially of beverage bottles, is made of recycled PET (r-PET). To date, the r-PET was provided first, and was only then mixed with the v-PET. This was preferably done immediately before using the raw material, for example, immediately upstream of an injection molding machine for producing preforms. However, virgin PET needs drying prior to its use, since it inevitably absorbs moisture. To this end, a drying oven is required.
It is known, for example, from WO 2006/099976 that, on the other hand, the r-PET is cooled as it leaves the recycling process, before being introduced into the preform production process. Prior to the plasticization of the PET material, a mixing ratio which is optimal for the preform production process (e.g. 50:50) is provided for both materials, the cooled r-PET and the dried v-PET, which requires a lock or a mixing chamber.